During flight, the rudder unit of an airplane is often subjected to considerable air loads affecting the outer skin of the rudder unit. Such wind loads are removed as a lateral force via the spars of the rudder unit (see FIGS. 1 and 2) into the airplane fuselage. The connection of the spars of the rudder unit is then usually performed with a double shear splice joint. This splice joint is frequently composed of a bracket clip, which is riveted to the airplane fuselage and provided with two bores, as well as two pairs of butt straps, which are bolted in two sections on either side of the bracket clip with the spar of the rudder unit through corresponding bores.
In order for the high strains in the spars to be safely removed into the airplane fuselage, the spars are provided in the joining area with frequently very large oversizes in order to reduce the strains on the bore face resulting from the forces transmitted from the bolts to the bore walls. As the forces are then removed from the butt straps into the bracket clip, the bracket clip also has to have a correspondingly large thickness so that the strains on the bore face occurring in the bores can be kept as low as possible.
This solution proves to be a problem in that for transmission into the airplane fuselage, the loads equally distributed over the spars are first locally concentrated on the connecting bolt and generate very high strains on the bore face in the bores in the bracket clip as well as in the spars themselves. However, the dimensions required due to this load concentration in the joining area of the spars cause considerable extra weight, which is of course undesirable in the field of aerospace technology.